Prime mover control device of construction machine

ABSTRACT

A prime mover control device of a construction machine includes a hydraulic pump ( 24 ) driven by a prime mover ( 10 ), an actuator ( 5 ) driven with pressure oil discharged from the hydraulic pump ( 24 ), and a control valve ( 25 ) that controls a flow of the pressure oil from the hydraulic pump ( 24 ) to the actuator ( 5 ) in response to an operation of a first operating member ( 22   a ). The prime mover control device includes a first set means ( 41 ) that sets a first set rotation speed Nt of the prime mover ( 10 ) according to the operation of the first operating member ( 22   a ), a second set means ( 43 ) that sets a second set rotation speed Nx of the prime mover ( 10 ) according to an operation of a second operating member ( 34 ), a selection member ( 35 ) that selects one of a first mode and a second mode, and a rotation speed control means ( 30, 13 ) that controls a prime mover rotation speed to match with a maximum value of the first set rotation speed Nt and the second set rotation speed Nx when the selection member ( 35 ) selects the first mode, and controls the prime mover rotation speed to match with the second set rotation speed Nx when the selection member ( 35 ) selects the second mode.

TECHNICAL FIELD

The present invention relates to a prime mover control device of aconstruction machine that is capable of changing a rotation speed of aprime mover in accordance with an operation amount.

BACKGROUND ART

Control devices of this type known in the related art include the onedisclosed in Japanese Patent Registration No. 2634330.

The device disclosed in this publication sets a rotation speed accordingto an operation amount of a rotation speed setting unit (a fuel lever)and a rotation speed according to an extent to which a travel pedal isoperated, and selects a maximum value as a target rotation speed. As aresult, a lowest value of the target rotation speed is restricted to arotation speed in correspondence to an operation amount of the rotationspeed setting unit so that if a rotation speed setting is set by therotation speed setting unit to a value suitable for working (e.g.,excavation), it is possible to minimize a fluctuation in the enginerotation speed and to improve the operability. Moreover, by setting therotation speed setting at the rotation speed setting unit to the idlingrotation speed during traveling, the prime mover rotation speed changesin accordance with the operation amount of the travel pedal, and thusthe improvement of the fuel efficiency and the noise reduction can beachieved.

When utilizing the device disclosed in the above mentioned publication,it is necessary to maintain the travel pedal at a position depressedhalfway down in order for a vehicle, for example, to travel at aconstant speed since the traveling speed of the vehicle is adjusted byadjusting the operation amount of the travel pedal. However, it is aburden on an operator to keep the travel pedal at the halfway-downposition.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a prime mover controldevice of a construction machine with which a traveling speed can beadjusted with ease.

The present invention is adopted in a construction machine having ahydraulic pump driven by a prime mover, an actuator driven with pressureoil discharged from the hydraulic pump, and a control valve thatcontrols a flow of the pressure oil from the hydraulic pump to theactuator in response to an operation of a first operating member. Theprime mover control device includes a first set means for setting afirst set rotation speed of the prime mover according to the operationof the first operating member, a second set means for setting a secondset rotation speed of the prime mover according to an operation of asecond operating member, a selection member that selects one of a firstmode and a second mode, and a rotation speed control means forcontrolling a prime mover rotation speed to match with a maximum valuebetween the first set rotation speed and the second set rotation speedwhen the selection member selects the first mode, and for controllingthe prime mover rotation speed to match with the second set rotationspeed when the selection member selects the second mode.

Another prime mover control device of the construction machine accordingto the present invention includes a first set means for setting a firstset rotation speed of the prime mover according to the operation of thefirst operating member, a second set means for setting a second setrotation speed of the prime mover according to an operation of a secondoperating member, a selection member that selects one of a first modeand a second mode, and a rotation speed control means for controlling aprime mover rotation speed to match with the first set rotation speedwhen the selection member selects the first mode, and for controllingthe prime mover rotation speed to match with the second set rotationspeed when the selection member selects the second mode.

Accordingly, since the drive speed of the actuator can be changed inaccordance with the operation amount of the second operating memberwhile the first operating member is operated to the maximum extent inthe second mode, the speed of the actuator can be adjusted with ease.

It is preferable that the first operating member is a foot-operatedoperating member, and the second operating member is a hand-operatedoperating member.

It is preferable that the selection member is installed in the vicinityof the second operating member. The actuator may be a traveling motor.

When the traveling state is determined by determining whether thetraveling state or work state, the first set rotation speed may be setto a larger value compared to a value to be set when the work state isdetermined. The traveling state may be determined when the non-operatingstate of the brake and the neutral operation are detected.

The present invention is ideal in an application in a wheeled hydraulicexcavator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of a wheeled hydraulic excavator in which thepresent invention is adopted;

FIG. 2 is a circuit diagram of a hydraulic circuit for traveling in thewheeled hydraulic excavator in FIG. 1;

FIG. 3 is a circuit diagram of a work hydraulic circuit in the wheeledhydraulic excavator in FIG. 1;

FIG. 4 is a block diagram of a prime mover control device achieved in anembodiment of the present invention;

FIG. 5 shows in detail a control circuit in FIG. 4;

FIG. 6 presents a flow chart a procedure for controlling the enginerotation speed;

FIG. 7 shows one example of arrangement of a set dial and a change-overswitch; and

FIG. 8 shows a variation example of FIG. 5.

BEST MODE FOR CARRYING OUT THE INVENTION

The first embodiment achieved by adopting a prime mover control deviceaccording to the present invention in a wheeled hydraulic excavator isexplained in reference to FIGS. 1 through 6.

As shown in FIG. 1, the wheeled hydraulic excavator includes anundercarriage 1 and a revolving superstructure 2 rotatably mounted atopthe undercarriage 1. An operator's cab 3 and a work front attachment 4constituted with a boom 4 a, an arm 4 b and a bucket 4 c are provided atthe revolving superstructure 2. The boom 4 a is raised/lowered as a boomcylinder 4 d is driven, the arm 4 b is raised/lowered as an arm cylinder4 e is driven and the bucket 4 c is engaged in a dig/dump operation as abucket cylinder 4 f is driven. A traveling motor 5, which ishydraulically driven, is provided at the undercarriage 1, and therotation of the traveling motor 5 is transmitted to wheels 6 (tires) viaa drive shaft and an axle.

FIG. 2 is a circuit diagram of a traveling hydraulic circuit in thewheeled hydraulic excavator shown in FIG. 1. This hydraulic circuitincludes a main pump 24 driven by a prime mover 10, the traveling motor5 driven with pressure oil form the main pump 24, a control valve 25that controls a flow of the pressure oil from the main pump 24 to thetraveling motor 5, a pilot pump 21, a pilot valve 22 driven via afoot-operated travel pedal 22 a, and a forward/backward switching valve23 that is switched to a forward position, a backward position or aneutral position in response to an operation of a forward/backwardselector switch (not shown).

As the forward/backward switching valve 23 is set to the forwardposition or the backward position through a switch operation and thenthe travel pedal 22 a is operated, a pilot pressure originating from thepilot pump 21 is applied to the control valve 25. In response, thepressure oil from the main pump 24 is applied to the traveling motor 5via the control valve 25 and the traveling motor 5 rotates, therebycausing the vehicle to travel forward or backward. A pressure sensor 31is connected to the pilot valve 22 and a pilot pressure Pt is detectedas a travel command with the pressure sensor 31.

FIG. 3 shows a hydraulic circuit for the boom cylinder, representing anexample of a work hydraulic circuit. This hydraulic circuit includes amain pump 26, the boom cylinder 4 d that is caused to extend/contract bypressure oil from the main pump 26, a control valve 27 that controls theflow of the pressure oil from the main pump 26 to the boom cylinder 4 d,the pilot pump 21 and a pilot valve 28 driven via an operating lever 28a. It is to be noted that although not shown, hydraulic circuits of theother actuators for actuating the front attachment are similar to thatdescribed above.

In response to an operation of the operating lever 28 a, the pilot valve28 is driven in correspondence to the extent to which the operatinglever 28 a has been operated and a pilot pressure from the pilot pump 21is applied to the control valve 27. As a result, the pressure oil fromthe main pump 26 is guided to the boom cylinder 4 d via the controlvalve 27 and, as the boom cylinder 4 d extends/contracts, the boom 4 ais raised/lowered. It is to be noted that the hydraulic circuit maydispense with the main pump 26 and, in such a case, the cylinder 4 d canbe driven with the pressure oil from the main pump 24.

In this embodiment, the engine rotation speed is controlled to adjust adelivery flow rate from the pump in a pedal mode (a first mode) or in adial mode (a second mode) to be detailed later, so as to adjust thevehicle speed.

FIG. 4 is a block diagram of a control circuit that controls therotation speed of the engine. A governor lever 11 of an engine 10 isconnected to a pulse motor 13 via a link mechanism 12 and the enginerotation speed is adjusted with the rotation of the pulse motor 13.Namely, the engine rotation speed increases as the pulse motor 13rotates forward, and the engine rotation speed decreases with a reverserotation of the pulse motor 13. A potentiometer 14 is connected to thegovernor lever 11 via the link mechanism 12, and the governor leverangle corresponding to the rotation speed of the engine 10, which isdetected with the potentiometer 14, is input to the control circuit 30as an engine control rotation speed Nθ.

The control circuit 30 is connected with the pressure sensor 31 thatdetects the pilot pressure Pt corresponding to the extent to which thetravel pedal 22 a is operated, a brake switch 32, a position sensor 33that detects the position to which the forward/backward switching valve23 is switched, a manual or hand-operated set dial 34 that issues asignal for setting the engine rotation speed in accordance with anextent X to which the dial is turned, and a change-over switch 35 thatchanges over between the pedal mode and the dial mode selectively.

As the brake switch 32 is switched to a traveling position, a workposition or a parking position, a work or traveling signal is outputfrom the brake switch 32. When the brake switch 32 is switched to thetraveling position, a parking brake is canceled and the operation of aservice brake is enabled through a brake pedal. As the brake switch 32is switched to the work position, the parking brake and the servicebrake are both engaged. When it is switched to the parking position, theparking brake is engaged. As the brake switch 32 is switched to thetraveling position, it outputs an off signal, whereas it outputs an onsignal when it is switched to the work or parking position.

The set dial 34 is installed in an operation panel in the vicinity of anoperator's seat so as to be operatable during traveling. The change-overswitch 35 is disposed adjacent to the set dial 34 so as to enable theoperator to operate the change-over switch 35 without leaving his handfrom the set dial 34. One example of arrangement of the set dial 34 andthe change-over switch 35 is shown in FIG. 7.

The rotation speed control circuit 30 executes the following arithmeticoperation and outputs a control signal to the pulse motor 13.

FIG. 5 is a conceptual diagram illustrating in detail the rotation speedcontrol circuit 30. The relationships between the detection value Ptprovided by the pressure sensor 31 and a target rotation speed Nt andbetween the detection value Pt and a target rotation speed Nd are storedin memory in advance at rotation speed calculation units 41 and 42respectively as shown in the figure, and the target rotation speeds Ntand Nd matching the extent to which the travel pedal 22 a is operatedare individually calculated based upon the characteristics of theserelationships. It is to be noted that the characteristics stored inmemory at the rotation speed calculation unit 41 are the characteristicssuited for traveling, whereas the characteristics stored in memory atthe rotation speed calculation unit 42 are the characteristics suitedfor work performed by using the work attachment 4. These characteristicsindicate linear increases in the target rotation speeds Nt and Nd fromthe idling rotation speed Ni as the extent of pedal operation increases.The target rotation speed Nt increases in a steeper slope compared tothe target rotation speed Nd, and a maximum value Ntmax of the targetrotation speed Nt is greater than a maximum value Ndmax of the targetrotation speed Nd.

As shown in the figure, the relationship between the extent X to whichthe set dial 34 is operated and a target rotation speed (rotation speedsetting) Nx is stored in memory in advance at a rotation speedcalculation unit 43 as shown in the figure, and the target rotationspeed Nx corresponding to the dial operation extent X is calculatedbased upon the characteristics of the relationship. It is to be notedthat a maximum value Nxmax of the target rotation speed Nx is set equalto the maximum value Ndmax at the rotation speed calculation unit 42(Nxmax=Ndmax).

A selection unit 44 selects one of the target rotation speeds Nt and Ndprovided by the rotation speed calculation units 41 and 42, based uponthe signals provided from the brake switch 32, the position sensor 33and the pressure sensor 31. If the brake switch 32 has been switched tothe traveling position (an off signal is output), the forward/backwardswitching valve 23 is set at a position other than the neutral positionand the pilot pressure Pt representing the extent of the operation ofthe travel pedal 22 a is equal to or greater than a predetermined value,i.e., if the vehicle is traveling, the target rotation speed Nt isselected, and the target rotation speed Nd is selected otherwise, i.e.,under non-traveling conditions.

A maximum value selection unit 45 compares the target rotation speed Ntor Nd selected by the selection unit 44 with the target rotation speedNx calculated at the rotation speed calculation unit 43 and selects thelarger value as Nmax.

A mode change unit 46 selects either the target rotation speed Nmaxselected at the maximum value selection unit 45 or the target rotationspeed Nx calculated at the rotation speed calculation unit 43, basedupon the signal provided from the change-over switch 35. The targetrotation speed Nmax is selected when the change-over switch 35 isswitched to the pedal mode, and the target rotation speed Nx is selectedwhen the change-over switch 35 is switched to the dial mode.

A servo control unit 47 compares the rotation speed (the rotation speedcommand value Nin) selected at the mode change unit 46 with the controlrotation speed Nθ corresponding to the displacement quantity of thegovernor lever 11 detected with the potentiometer 14. Then, it controlsthe pulse motor 13 through the procedure shown in FIG. 6 so as to matchthe two values.

First, the rotation speed command value Nin and the control rotationspeed Nθ are individually read in step S21 before proceeding to step S22in FIG. 6. Then, in step S22, the results of subtracting Nin from Nθ arestored as a rotation speed difference A in memory, and in step S23, adecision is made as to whether or not |A|≧K is true with regard to therotation speed difference A and a predetermined reference rotation speeddifference K. If an affirmative decision is made, the operation proceedsto step S24 to decide whether or not the rotation speed difference A isgreater than 0. If A>0, the control rotation speed Nθ is greater thanthe rotation speed command value Nin, i.e., the control rotation speedis higher than the target rotation speed and, accordingly, a signalconstituting a command for a motor reverse rotation is output to thepulse motor 13 in step S25 in order to lower the engine rotation speed.In response, the pulse motor 13 rotates in the reverse direction,thereby lowering the engine rotation speed.

If, on the other hand, A≦0, the control rotation speed Nθ is lower thanthe rotation speed command value Nin, i.e., the control rotation speedis lower than the target rotation speed and, accordingly, a signalconstituting a command for a motor forward rotation is output in stepS26 in order to raise the engine rotation speed. In response, the pulsemotor 13 rotates forward, thereby raising the engine rotation speed. Ifa negative decision is made in step S23, the operation proceeds to stepS27 to output a motor stop signal and, as a result, the engine rotationspeed is sustained at a constant level. Once the processing in one ofsteps S25 through S27 is executed, the operation returns to the startpoint.

Next, the operation that characterizes the prime mover control deviceachieved in this embodiment is explained.

(1) Pedal Mode

First, explanation is given in the case where the pedal mode is selectedwith the change-over switch 35. By selecting the pedal mode, the enginerotation speed can be set in accordance with the operation of the travelpedal 22 a and thus, the pedal mode is suitable for a normal travelduring which a maximum torque may be generated.

The brake switch 32 is set to the traveling position and theforward/backward selector switch is set to the forward position or thebackward position when the vehicle is to travel. As the travel pedal 22a is depressed in this state, the control valve 25 is switched incorrespondence to the extent of the pedal operation and the travelingmotor 5 is caused to rotate by the pressure oil from the main pump 24.

At this time, the target rotation speed Nt is selected through thearithmetic operation in the selection unit 44 of the control circuit 30,and the target rotation speed Nt is again selected in the maximum valueselection unit 45. Thus, the target rotation speed Nt is set as therotation speed command value Nin, and with the signal outputted throughthe servo control to the pulse motor 13, control is implemented to setthe engine rotation speed equal to the target rotation speed Nt. In thissituation, the engine rotation speed is adjusted in conformance to thecharacteristics suitable for traveling stored in memory at the rotationspeed calculation unit 41. As a result, an improvement in fuelefficiency and the noise reduction can be achieved as well as achievingdesirable acceleration.

To engage the vehicle in work in a state where the vehicle remainsstopping, the brake switch 32 is set to the work position and theforward/backward selector switch is set to the neutral position. As theoperating lever 28 a is operated in this state, the control valve 27 isswitched in correspondence to the extent to which the operating lever 28a is operated, thereby driving the boom cylinder 4 d.

At this time, based upon the arithmetic operation executed at thecontrol circuit 30, the selection unit 44 selects the target rotationspeed Nd and the maximum value selection unit 45 selects a larger valuebetween the target rotation speed Nd and the target rotation speed Nxset by the set dial 34. Accordingly, by setting the target rotationspeed Nx with the set dial 34 to a suitable value for the particularnature of work to be undertaken, a fluctuation of the engine rotationspeed can be suppressed regardless of the operation of the travel pedal22 a and the excellent workability can be obtained.

(2) Dial Mode

Next, explanation is given in the case where the dial mode is selectedwith the change-over switch 35. In the dial mode, the engine rotationspeed is set through the operation of the set dial 34 regardless of theoperation of the travel pedal 22 a, and the engine rotation speed isadjusted to the value set via the set dial 34 while no rotation speed isselected at the selection units 44 and 45 with reference to FIG. 5. Inthis mode, the engine rotation speed is set via the set dial 34 and whenthe travel pedal 22 a is depressed, only an extent to which the controlvalve 25 is switched changes to adjust the speed without changing theengine rotation speed. Accordingly, by setting the engine rotation speedto, for example, a predetermined low rotation speed with the set dial34, a speed based upon a maximum delivery flow rate of the main pump 24corresponding to the set engine rotation speed can be set as a maximumspeed, thereby making the dial mode suitable for a case where the travelspeed should be limited below a predetermined level or for a case wherethe vehicle travels at a constant speed.

The target rotation speed Nx set via the set dial 34 is selected at themode change unit 46 in the dial mode, and the target rotation speed Nxis set as the rotation speed command value Nin. As a result, the enginerotation speed is controlled to the target rotation speed Nx regardlessof the operation of the travel pedal 22 a. Namely, the delivery flowrate of the pump changes according to the extent to which the dial isturned.

Accordingly, when depressing the travel pedal 22 a to the maximumextent, the pressure oil according to the target rotation speed Nx issupplied to the traveling motor 5 so as to enable the maximum speed ofthe vehicle to be regulated in accordance with the operation of the setdial 34. The maximum travel speed rises as the engine rotation speedincreases due to increase in the extent to which the dial is operated,whereas the maximum travel speed is lowered as the engine rotation speeddecreases due to decrease in the dial operation amount. In this manner,the vehicle can travel at a constant speed which is set at will whilethe travel pedal 22 a is depressed to the maximum extent. As a result,there is no need for the operator to adjust the pedal operation amount,thereby reducing the burden on the operator.

According to this embodiment the following advantages can be achieved.

(1) The pedal mode or the dial mode is selected according to theoperation of the change-over switch 35. The larger value between thetarget rotation speed Nt or Nd based upon the pedal operation and thetarget rotation speed Nx in accordance with the dial operation isselected in the pedal mode, whereas the target rotation speed Nxaccording to the dial operation is selected in the dial mode.Accordingly, in the dial mode the travel speed of the vehicle when thetravel pedal 22 a is depressed to the maximum extent is adjusted to thevalue in accordance with the extent X to which the dial is turned. As aresult, the vehicle speed can be adjusted easily so as to allow thevehicle to travel at a constant speed with ease. In the pedal mode themaximum driving torque can be generated, thereby allowing the vehicle totravel at high speed with ease.

(2) The change-over switch 35 can be operated without releasing anoperator's hand from the set dial 34 because the change-over switch 35is installed in the vicinity of the set dial 34. As a result, constantspeed travel and normal travel can be changed over immediately.

(3) The characteristics of the target rotation speed Nt for travelingand the target rotation speed Nd for working are set individually sothat an inclination of increase in the target rotation speed Nt fortraveling and the maximum rotation speed Ntmax are greater than aninclination of increase in target rotation speed Nd for working and amaximum value Ndmax, respectively. In this manner, excellentacceleration can be achieved during traveling in the pedal mode and theengine rotation speed can be adjusted easily during working since theinclination of the target rotation speed Nd for working is small.

(4) By detecting a state of traveling and a state of working with thebrake switch 32 and the position sensor 33 and selecting the targetrotation speed Nt or Nd based on the detection result, a specialoperation for selecting the target rotation speed is not necessary.

It is to be noted that while three target rotation speed calculationunits 41 to 43 are provided in the above-described embodiment, thecontrol circuit may dispense with the target rotation speed calculationunit 42. While the change-over switch 35 constitutes a selection means,an operation member other than the switch, for instance a dial may beused. While the set dial 34 constitutes a second set member, anoperation member other than the dial, for instance a push button switchor a slide switch which moves straight may be used instead. While atravel state is determined based upon the signals from the brake switch32 and the position sensor 33 working as a determination means, thetravel state may be determined using, for instance a vehicle speedsensor.

While, in the above embodiment, a maximum value of the target rotationspeed Nt or Nd and the target rotation speed Nx is selected at themaximum value selection unit 45, the maximum value selection unit 45 maybe omitted as shown in FIG. 8. In this manner, the engine rotation speedcan be set in accordance with the operation of the travel pedal 22 aregardless of the operation of the set dial 34 in the pedal mode, andthe engine rotation speed can be set in accordance with the operation ofthe set dial 34 in the dial mode. That is, a separate engine control canbe executed by using either the travel pedal 22 a or the set dial 34.

While the explanation is given to an example that facilitates the speedadjustment of the traveling hydraulic motor 5 in the above, the presentinvention is not to be limited to this example and it may be applied toa revolving hydraulic motor that revolves the revolving superstructure,for example. A first operating member is also not limited to the travelpedal 22 a.

INDUSTRIAL APPLICABILITY

While an explanation is given above on an example in which a wheeledhydraulic excavator represents an example of a construction machine inwhich the present invention may be adopted, the present invention mayalso be adopted in other types of construction machines such asnon-wheel construction machines.

1-8. (canceled)
 9. A prime mover control device of a constructionmachine that includes: a hydraulic pump driven by a prime mover; anactuator driven with pressure oil discharged from the hydraulic pump;and a control valve that controls a flow of the pressure oil from thehydraulic pump to the actuator in response to an operation of a firstoperating member, comprising: a first set device that sets a first setrotation speed of the prime mover according to the operation of thefirst operating member; a second set device that sets a second setrotation speed of the prime mover according to an operation of a secondoperating member; a selection member that selects one of a first modeand a second mode; and a rotation speed control device that controls aprime mover rotation speed to match with a maximum value between thefirst set rotation speed and the second set rotation speed when theselection member selects the first mode, and that controls the primemover rotation speed to match with the second set rotation speed whenthe selection member selects the second mode.
 10. A prime mover controldevice of a construction machine that includes: a hydraulic pump drivenby a prime mover; an actuator driven with pressure oil discharged fromthe hydraulic pump; and a control valve that controls a flow of thepressure oil from the hydraulic pump to the actuator in response to anoperation of a first operating member, comprising: a first set devicethat sets a first set rotation speed of the prime mover according to theoperation of the first operating member; a second set device that sets asecond set rotation speed of the prime mover according to an operationof a second operating member; a selection member that selects one of afirst mode and a second mode; and a rotation speed control device thatcontrols a prime mover rotation speed to match with the first setrotation speed when the selection member selects the first mode, andthat controls the prime mover rotation speed to match with the secondset rotation speed when the selection member selects the second mode.11. A prime mover control device of a construction machine according toclaim 9, wherein: the first operating member is a foot-operatedoperating member, and the second operating member is a hand-operatedoperating member.
 12. A prime mover control device of a constructionmachine according to claim 9, wherein: the selection member is installedin the vicinity of the second operating member.
 13. A prime movercontrol device of a construction machine according to claim 9, wherein:the actuator is a traveling motor.
 14. A prime mover control device of aconstruction machine according to claim 13, further comprising: adetermination device that determines a traveling state and a work state;wherein: when the traveling state is determined with the determinationdevice, the first set device sets the first set rotation speed to alarger value compared to a value to be set when the work state isdetermined.
 15. A prime mover control device of a construction machineaccording to claim 14, wherein: the determination device comprises abrake detection unit that detects a non-operating state of a brake and aneutral detection unit that detects a neutral operation of the firstoperating member, and determines the traveling state when thenon-operating state of the brake is detected and the neutral operationis not detected.
 16. A wheeled hydraulic excavator, comprising: ahydraulic pump driven by a prime mover; an actuator driven with pressureoil discharged from the hydraulic pump; a control valve that controls aflow of the pressure oil from the hydraulic pump to the actuator inresponse to an operation of a first operating member; and a prime movercontrol device according to claim
 9. 17. A prime mover control device ofa construction machine according to claim 10, wherein: the firstoperating member is a foot-operated operating member, and the secondoperating member is a hand-operated operating member.
 18. A prime movercontrol device of a construction machine according to claim 10, wherein:the selection member is installed in the vicinity of the secondoperating member.
 19. A prime mover control device of a constructionmachine according to claim 10, wherein: the actuator is a travelingmotor.
 20. A prime mover control device of a construction machineaccording to claim 19, further comprising: a determination device thatdetermines a traveling state and a work state; wherein: when thetraveling state is determined with the determination device, the firstset device sets the first set rotation speed to a larger value comparedto a value to be set when the work state is determined.
 21. A primemover control device of a construction machine according to claim 20,wherein: the determination device comprises a brake detection unit thatdetects a non-operating state of a brake and a neutral detection unitthat detects a neutral operation of the first operating member, anddetermines the traveling state when the non-operating state of the brakeis detected and the neutral operation is not detected.